Steel belt for a rotary press

ABSTRACT

A dark coloured heat-absorbing layer provided on the inner face of an endless steel belt in a rotary press for continuous pressing of materials to provide uniform absorption of heat by the belt from the heating means.

United States Patent [11] 3,850,093

Gersbeck Nov. 26, 1974 STEEL BELT FOR A ROTARY PRESS [75] Inventor: RolfGersbeck, I-Iannover, Germany [5 6] Referencessclted UNIT TATE PATE [73]Assignee: Hermann Berstorff Maschinenbau ED S NTS GmbH,HannOvepKleef-eld, 3,266,169 8/1966 Smith, Jr", 165/133 X GermanyFOREIGN PATENTS OR APPLICATIONS Feb. 485,242 5/1938 Great Britain 100/93RP [21] Appl. No.: 330,750 Primary Examiner-Peter Feldman Attorney,Agent, or Firm-Donald D. Jeffery [30] Foreign Application Priority DataABSTRACT Feb 12, 1972 Germany 2206710 A dark coloured heat absorbinglayer provided on the [52] U S Cl 100/93 RP 00 /1 51 425/373 inner faceof an endless steel belt in a rotary press for [51] 302C 1l/08 B30b15/34 continuous pressing of materials to provide uniform [58] Fie'ld/93 RP 38 151454. absorption of heat by the belt from the heating means.

4 Claims, 2 Drawing Figures STEEL BELT FOR A ROTARY PRESS The inventionrelates to steel belts for rotary presses.

Rotary presses incorporating endless steel belts can be used forcontinuous pressing of chip-wood plates or for continuous vulcanisingand/or hardening and crosslinking of webs of rubber and syntheticplastics material.

Such steel belts may be formed from a steel strip with its ends weldedtogether transversely and, in order to obtain a working width of, forexample, 2.50 m, may be formed by longitudinally welding togetherseveral narrow steel belts. The welds are subsequently ground smooth onthe inner and outer faces of the belt to obtain smooth surfaces for thebelt.

Steel belts formed by welding together several narrow steel belts, havea high tensile strength; however, they also have the disadvantage thattheir inner faces do not have a uniform reflecting capacity, that is tosay the smoothly polished welds are brighter than the remainder andtherefore they reflect heat radiations more strongly. The severalwelded-together narrow steel belts may themselves have differentreflection capacities and may also have marks on them.

The heat reflection and therefore the heat transmission of the steelbelts, thus is non-uniform during heating by means of radiation heatingmeans, and material to be pressed in the rotary press is heatednonuniformly. Consequently, during, for example, continuousvulcanisation of rubber webs, a web portion which lies adjacent abrightly polished weld of the endless steel belt will be vulcanised to alesser degree than a web portion which lies adjacent another portion ofthe endless steel belt and weak portions of the web may thus beproduced.

In the case of continuous pressing of chips to form a chip-wood plate,portions of the plate which lay adjacent a weld of the endless steelbelt during pressing may be visibly distinguishable on the finishedchip-wood plate, because these places were subjected to a lowertemperature during pressing.

According to the invention there is provided on an endless steel belt ina rotary press for continuous pressing of chip-wood plates, or forcontinuous vulcanising and/or hardening and cross-linking of rubber andsyntheric plastics material webs, where material to be treated ispressed between the endless steel belt and a heated rotating drum, adark coloured heababsorbing coating provided on the inner face of theendless steel belt.

In a further development of the invention, the inner side of the endlesssteel belt may be darkly browned.

The dark coloured heat-absorbing layer on the inner face of the endlesssteel belt may be an inorganic pigment, for example an iron oxide black.

Through this measure according to the invention, it is achieved that theheat absorption on the entire inner side of the endless steel belt isuniform, and therefore also the material to be treated is subjected to auniform temperature.

The invention is diagrammatically illustrated by way of example in theaccompanying drawing, in which:

FIG. 1 shows an endless steel belt, for a rotary steel press, accordingto the invention, the inner face of which has been surface treated, and

, sides of the welds of the belt I so formed are polished smooth and theinner face of the endless belt I is coated with a dark coloured layer3.which absorbs heat.

In the rotary press shown in FIG. 2, the material 4 to be treated isexposed to high temperature and pressure when passed between the endlesssteel belt 1, which is looped round a lower roll 5 and an upper roll 9and a heated drum 6, around which drum 6 the belt is looped. The endlesssteel belt 1 is set under pressure by a roll 7, by means known per se,for example hydraulic rams which act in the direction of the arrow 8.The inner face of the endless steel belt 1 which bears the coating 3,while the endless steel belt 1 is looped around the drum 6, is heated upby heat radiation means 10, for example infra-red or quartz radiators,in order to raise the material to be pressed to a desired temperature.Since the inner face of the endless steel belt 1 has the dark colouredlayer 3, it absorbs heat uniformly and thus the material to be pressedis heated uniformly over its entire cross-section, because thereflection of heat, produced by the heating device 10, from the endlesssteel belt 1 is completely uniform.

Due to the application of a dark heat-absorbing layer 3 onto the innerside of the endless steel belt 1 furthermore it is achieved that theendless steel belt 1 and the material 4 can be heated substantially morerapidly.

Comparison test carried out with a smoothlypolished endless steel beltand with a steel belt with a dark coloured heat-absorbing layer producedthe following results:

Steel belt with heat-absorbing layer Steel belt without hcat-absorbinglayer after 3 minutes to C after 6 minutes to l50 C after 30 minutes to260 C From these tests it is clear that a rotary press with an endlesssteel belt provided on its inner face with a heatabsorbing layer, can bebrought substantially more rapidly to the required working temperature,and that, due to the substantially better heat-transmission,correspondingly less heat energy is used, and thus it operatessubstantially more economically.

A further advantage is achieved in that the steel belt, which isprovided with a heat-absorbing layer on its inner side, no longerrequires to be protected, prior to use, with an anti-corrosionprotective compound and therefore there is no need for the previouslynecessary operation of removing the anti-corrosion protective layer,before the press is set in operation.

It is particularly advantageous if the inner side of the endless steelbelt is browned, that is to say bronzed or black finished, because sucha browning hardly shows any wear phenomena. The heat-absorbing coatingis advantageously an inorganic pigment, for example iron oxide black,because such pigments are unaffected by temperatures up to about 500C.

What is claimed is:

l. A rotary press for the continuous temperature and pressure treatmentof materials fed thereto comprising:

c an endless steel belt looped around said rollers in pressureengagement withsaid material as it passes around in direct contact withsaid heated drum, said belt comprising a plurality of relatively narrowbelt sections longitudinally welded at their adjoining edges, whichedges are thereafter polished smooth for uniform, non-abrading contactwith said material, and a dark coloured heat-absorbing coating providedon the entire inner face of said endless steel belt.

2. The rotary press of claim 1 wherein said coating on said steel beltis brown in color.

3. The rotary press of claim 1 wherein said dark colored coating is aninorganic pigment.

4. The rotary press of claim 3 wherein said inorganic pigment is ironoxide black.

1. A rotary press for the continuous temperature and pressure treatmentof materials fed thereto comprising: a. a heated drum, including radiantheating means adjacent said drum for heating the same by radiation, b. aplurality of rollers, including upper and lower rollers spaced partiallyabove and below said heated drum at the inlet side thereof and a tensionroller at the opposite side of said heated drum, said upper and lowerrollers being positioned closely adjacent said heated drum formaintaining pressure on said material as it passes around said drum, tHeimprovement comprising; c. an endless steel belt looped around saidrollers in pressure engagement with said material as it passes around indirect contact with said heated drum, said belt comprising a pluralityof relatively narrow belt sections longitudinally welded at theiradjoining edges, which edges are thereafter polished smooth for uniform,non-abrading contact with said material, and a dark colouredheat-absorbing coating provided on the entire inner face of said endlesssteel belt.
 2. The rotary press of claim 1 wherein said coating on saidsteel belt is brown in color.
 3. The rotary press of claim 1 whereinsaid dark colored coating is an inorganic pigment.
 4. The rotary pressof claim 3 wherein said inorganic pigment is iron oxide black.